net: implement async HTTP/HTTPS requests for Windows and Linux.

build/autotools/m4/lol-conf.m4

@@ -84,6 +84,15 @@ if test "$ac_cv_have_getopt_long" != "no"; then
 fi
 
 
+dnl  Use OpenSSL?
+ac_cv_have_openssl=no
+AC_CHECK_LIB(ssl, OPENSSL_init_ssl,
+ [ac_cv_have_openssl=yes
+  AC_DEFINE(LOL_USE_OPENSSL, 1, Define to 1 to use OpenSSL)
+  LOL_LIBS="${LOL_LIBS} -lssl -lcrypto"])
+AM_CONDITIONAL(LOL_USE_OPENSSL, test "${ac_cv_have_openssl}" = "yes")
+
+
 dnl  Use Bullet Physics?
 ac_cv_my_have_bullet="no"
 if test "${enable_bullet}" != "no"; then

doc/tutorial/17_net.cpp

@@ -30,12 +30,20 @@ public:
     {
         entity::tick_game(seconds);
 
-        if (client.get_status() == lol::net::http::status::success)
+        switch (client.get_status())
         {
-            lol::msg::info("Downloaded %d bytes: %s\n",
+        case lol::net::http::status::success:
+            lol::msg::info("downloaded %d bytes: %s\n",
                            (int)client.get_result().size(),
                            client.get_result().c_str());
             client.reset();
+            break;
+        case lol::net::http::status::error:
+            lol::msg::info("error downloading %s\n", client.get_url().c_str());
+            client.reset();
+            break;
+        default:
+            break;
         }
     }
 

src/lol/net/http.h

@@ -23,8 +23,6 @@ namespace net
 namespace http
 {
 
-class client_impl;
-
 enum class status : uint8_t
 {
     ready   = 0,
@@ -33,6 +31,8 @@ enum class status : uint8_t
     error   = 3,
 };
 
+class client_impl;
+
 class client
 {
 public:
@@ -45,8 +45,9 @@ public:
     // Reset state
     void reset();
 
-    // Get status (may be pending) and result
+    // Get current URL, status (may be pending), and result
     status get_status() const;
+    std::string const & get_url() const;
     std::string const & get_result() const;
 
 private:

src/net/http.cpp

@@ -12,12 +12,20 @@
 
 #include <lol/engine-internal.h>
 
+#if LOL_USE_OPENSSL
+#   define CPPHTTPLIB_OPENSSL_SUPPORT 1
+#endif
+
 #if __EMSCRIPTEN__
 #   include <emscripten/fetch.h>
 #else
 #   include <httplib.h>
 #endif
 
+#include <utility>
+#include <memory>
+#include <regex>
+
 namespace lol
 {
 
@@ -31,11 +39,26 @@ class client_impl
 {
 public:
 #if __EMSCRIPTEN__
+    ~client_impl()
+    {
+        emscripten_fetch_close(impl->m_fetch);
+    }
+
+    void get(std::string const &url)
+    {
+        emscripten_fetch_attr_t attr;
+        emscripten_fetch_attr_init(&attr);
+        strcpy(attr.requestMethod, "GET");
+        attr.userData = impl.get();
+        attr.attributes = EMSCRIPTEN_FETCH_LOAD_TO_MEMORY;
+        attr.onsuccess = client_impl::on_success;
+        attr.onerror = client_impl::on_failure;
+        impl->m_fetch = emscripten_fetch(&attr, url.c_str());
+    }
+
     static void on_success(emscripten_fetch_t *fetch)
     {
         auto *that = (client_impl *)fetch->userData;
-        msg::info("finished downloading %llu bytes from URL %s.\n",
-                  fetch->numBytes, fetch->url);
         that->m_result.assign(fetch->data, fetch->numBytes);
         that->m_status = status::success;
     }
@@ -50,15 +73,59 @@ public:
 
     emscripten_fetch_t *m_fetch = nullptr;
 #else
-    void get(std::string const& url)
+    ~client_impl()
     {
+        delete m_thread;
+    }
 
+    void get(std::string const& url)
+    {
+        // This regex is copied from cpp-httplib
+        const static std::regex re(
+            R"(^(?:([^:/?#]+):)?(?://([^/?#]*))?([^?#]*(?:\?[^#]*)?)(?:#.*)?)");
+
+        std::smatch m;
+        if (!std::regex_match(url, m, re))
+        {
+            m_status = status::error;
+            return;
+        }
+
+        auto scheme = m[1].str();
+        auto host = m[2].str();
+        auto path = m[3].str();
+
+#ifdef CPPHTTPLIB_OPENSSL_SUPPORT
+        if (scheme == "https")
+            m_client = std::make_unique<httplib::SSLClient>(host);
+        else
+#endif
+        m_client = std::make_shared<httplib::Client>(host);
+        m_client->set_follow_location(true);
+
+        m_thread = new lol::thread([this, path](thread *)
+        {
+            auto res = m_client->Get(path.c_str());
+            if (res && res->status == 200)
+            {
+                m_result = std::move(res->body);
+                m_status = status::success;
+            }
+            else
+            {
+                msg::error("downloading %s failed, HTTP failure status code: %d.\n",
+                           m_url.c_str(), res ? res->status : -1);
+                m_status = status::error;
+            }
+        });
     }
 
-    //httplib::Client &client;
+    lol::thread *m_thread = nullptr;
+    std::shared_ptr<httplib::Client> m_client;
 #endif
 
     status m_status;
+    std::string m_url;
     std::string m_result;
 };
 
@@ -69,30 +136,19 @@ client::client()
 
 client::~client()
 {
-#if __EMSCRIPTEN__
-    emscripten_fetch_close(impl->m_fetch);
-#endif
 }
 
 void client::get(std::string const &url)
 {
     impl->m_status = status::pending;
-#if __EMSCRIPTEN__
-    emscripten_fetch_attr_t attr;
-    emscripten_fetch_attr_init(&attr);
-    strcpy(attr.requestMethod, "GET");
-    attr.userData = impl.get();
-    attr.attributes = EMSCRIPTEN_FETCH_LOAD_TO_MEMORY;
-    attr.onsuccess = client_impl::on_success;
-    attr.onerror = client_impl::on_failure;
-    impl->m_fetch = emscripten_fetch(&attr, url.c_str());
-#else
-#endif
+    impl->m_url = url;
+    impl->get(url);
 }
 
 void client::reset()
 {
     impl->m_status = status::ready;
+    impl->m_url.assign("");
     impl->m_result.assign("");
 }
 
@@ -101,6 +157,11 @@ status client::get_status() const
     return impl->m_status;
 }
 
+std::string const & client::get_url() const
+{
+    return impl->m_url;
+}
+
 std::string const & client::get_result() const
 {
     return impl->m_result;